Fusible safety valve mounting



Jan. 4, 1966 L. J. SIGL 3,227,170

FUSIBLE SAFETY VALVE MOUNTING Filed May 20, 1963 2 Sheets-Sheet 1INVENTOR.

Jan. 4, 1966 Filed May 20, 1965 L. J. SIGL FUSIBLE SAFETY VALVE MOUNTING2 Sheets-Sheet 2 INVENTOR law/s J. 5/64 A TTOQA/E Y5 United StatesPatent 3,227,170 FUSIBLE SAFETY VALVE MOUNTING Louis J. Sig], 1088Colvin Ave., Kenmore, N.Y. Filed May 20, 1963, Ser. No. 281,494 4Claims. (Cl. 137-73) This invention relates to safety devices forboilers or other apparatus subject to heat and pressure and moreparticularly, to safety valves associated with such apparatus in a novelmanner.

Safety valves for boilers and similar apparatus are of course wellknown. Such safety valves are subject to operational failure for variousreasons, especially after long periods when the necessity for operationof the valve has not arisen. In such cases the valve itself may becomestuck to the seat by corrosion, the valve mechanism may become fouled byforeign matter such as dirt or the like, and may fail to operate whenrequired and at the desired pressure for various other reasons.

Such safety valves are commonly provided with means for manually causingthe valve to raise from its seat for testing purposes but such testingmay be neglected and, even if periodically tested, there is no assurancethat the valve will operate at the desired pressure. Furthermore, due tolow liquid in a boiler, for instance, excessive temperatures may beattained without the presence of a proportionately high steamtemperature within the boiler or, more particularly, at the region ofthe boiler where the safety valve is located.

A further possible objection to safety valves as presently constructedand arranged resides in the fact that, even when it operates entirely asintended, a conventional safety valve merely relieves excessive pressureand then re-closes, leaving no clear or permanent indication that acondition requiring safety valve operation has existed.

The present safety valve construction and mounting is such that when apredetermined limit temperature occurs at the safety valve, the safetyvalve becomes entirely dis.- sociated from the boiler or other apparatusto which it is normally connected. This occurs through fusion ofmaterial which intervenes between the apparatus proper and the safetyvalve and thus forms a mounting connection therebetween.

In boilers and similar apparatus temperatures and pressures are closelyrelated and therefore, generally, unduly high boiler pressures andunduly high temperatures go hand in hand. With the safety valve mountingof the present invention, if the safety valve fails to open at apredetermined undue pressure, the low melting alloy which connects thesafety valve proper with the boiler fuses and the pressure thereagainstfrom within the boiler forces the entire valve structure from itsmounted position. A further feature of the apparatus of the presentinvention resides in the provision of means for automatically shuttingoff the supply of fuel to the boiler when an abnormal condition isreached and the Safety valve either opens under pressure from the boileror becomes dissociated therefrom by fusion of the low melting alloyportion of the safety valve mounting.

This may be accomplished by biasing a fuel valve or other fuel controlmember to closed position by a spring or the like and providing aconnection between the fuel valve of fuel control member and the valveelement of the safety valve. In a further modification the connection tothe fuel valve or other energy-supply control means leads from a fusibleconnection element which is disposed in the safety valve beyond thevalve element thereof, so that the fusible connection is exposed toescaping steam when the safety valve opens.

Thus in either modification if the valve element opens or if the valveassembly becomes dissociated from the 3,227,170 Patented Jan. 4, 1966boiler it releases the force which holds the fuel valve or fuel controlmember in open position, whereupon the fuel valve or fuel control memberimmediately closes. In the modification which includes a fusibleconnection which is exposed to steam when the safety valve opens, themelting of this connection serves as a permanent indication that thesafety valve has opened.

Several mechanical embodiments of the principles of the presentinvention are illustrated in the accompanying drawings and described inthe following specification. However, it is to be understood that suchembodiments are by way of example only and that various mechanicalmodifications may be made therein without departing from the principlesof the invention, the scope of which is limited only as defined in theappended claims.

In the drawings:

FIG. 1 is a vertical longitudinal cross-sectional view through one formof the safety valve of the present invention mounted upon a boiler orsimilar apparatus and with a-fuel control valve shown in associationtherewith; and r FIG. 2 is a similar view of a modified form of thesafety valve construction of the present invention.

In FIG. 1 of the drawing, the numeral 10 designates a steam boiler orsimilar apparatus such as a hot water heater, and the numeral 11designates a safety valve main housing member having a cup-shaped upperportion 12 and a reduced mounting sleeve portion 13. A connection memberdesignated generally by the numeral 14 comprises a lower threadedportion 15 which threads into the wall of the boiler 10 and an uppersleeve portion 16 which receives the stem 13 of safety valve housing 11loosely, whereby a relatively thin bushing of low melting alloy 17 maybe interposed therebetween. A nut formation 18 on connection member 14is provided for securing the same to the boiler.

The remainder of the construction of the safety valve per se is more orless conventional. Stem portion 13 terminates at its upper end withinthe cup-shaped portion 12 in a fiat radial valve seat and a valve member20 normally seats thereon, in which position the passage 21 through stem13 which leads from the interior of boiler 10 is closed. A vented capmember 23 is threaded into the upper end of cup-shaped portion 12 ofvalve housing 11 and bears against the upper end of a compression coilspring 24 which normally holds the valve in closed position.

A stem member 26 is connected at its lower end to valve element 20 andextends upwardly through the cap member 23. As is conventional, a levermember 27 is pivoted to stem 26 as at 28 and may be manually pivoted ina counterclockwise direction as viewed in the drawing to forcibly liftthe valve element 20 from its seat for testing purposes.

In the drawing, the numeral 30 designates a fuel supply line which maysupply gas or fuel oil to the burner which fires boiler 10. The numeral31 designates a valve interposed in such fuel line and, in theillustrated instance, the valve moves in a counterclockwise direction toopen position and in a clockwise direction to closed position. Anextension coil spring 32 acts against an arm 33 connected to the valveelement of valve 31 to urge the valve element to closed position while awire or similar connection 34 connects between the top of stem 26 and anarm 35 likewise pivotally movable with the valve element of valve 31.

From the foregoing it will be noted that opening movement of valve 20 inthe usual fashion by reason of excessive pressure thereagainst frompassage 21 relaxes the tension in wire 34 whereupon spring 32 closes thefuel valve.

H lfn-the valve failsto open-at a desired pressure by reason ofmalfunction, the excessive temperature accompanying such excessivepressure will fuse bushing 17 and'the pressure'upwardly against thevalve assembly will cause the stem 13 to move outwardly of the sleeveporton 16 of mounting member 14. This releases the pressure inthe boilerand likewise relaxes the tension of wire 34 which also closes fuel valve31 as described above.

Aneffective method of forming the soft metal bushing 17 and causing thesame to provide a secure joint between sleeve portion 13 and the sleeveportion 16 of connection member '14 is to first prepare the interior ofsleeve portion 16 and the exterior of sleeve portion 13 by tinning, thatis, applying a thin coating of solder to these surfaces. The parts arethen assembled and molten solder or other alloy having the desiredmelting point is poured into the radial space between the sleeveportions 13 and 16 to form bushing 17 which is thus securely bonded orfused to the adjacent sleeve surfaces.

Reference will now be had to the embodiment illustrated in FIG. 2wherein the numeral 40 designates a steam boiler or analogous apparatusand the numeral 41 designates a generally conventional safety valvehousing member comprising an upper valve chamber portion 42 and areduced external threaded mounting nipple portion 43. Aconnection memberdesignated generally by the numeral 44 comprises a lower threadedportion 45 which threads into the boiler 10 and an upper sleeve portion46 which receives a lower sleeve portion 45 of an internally'threadedvalve housing mounting member 48.

It will be noted that the sleeve portion 47 of the mounting member 48fits loosely within the upper sleeve portion 46 of connection member 44and, as in the case of the previous embodiment, a relatively thinannular layer of low melting alloy50 is interposed in the space betweenthe sleeve portions 46 and 47.

The remainder'of the safety valve construction is generally conventionalwith the exception of a further thermal connection element which will bedescribed presently. The mounting nipple portion 43 terminates at itsupper end within the valve chamber housing portion '42 in a flat radialvalve seat and a valve'member 52 normally seats'thereon, in whichposition an axial passage 53 from the interior of boiler 40 is closed. Acap member 55 threads into the upper end of housing portion 42 and bearsagainst the upper end of a compression coil spring 56 which normallyholds valve 52 in closed position.

A stern member 60 is connected at its lower end to valve element 52 andextends upwardly through the cap member 55. As in the previousembodiment, a valve testing lever. 62 is pivoted to the upper end. ofstem member 60.

. Again as inthe previous embodiment, afuel supply line designated65'has disposed therein a globe type shutoff valve 66 which is normallybiased to closed position by. an extension coil spring 67 acting throughan arm 68 fixed to the pivoted valve element of the globe valve 66. Afurther. arm 69 likewiseconnected to the valve element of valve;66 has awire or similar connection 70 leading to afusible connection meansdesignated generally by the numeral 71 anddisposed within an outletpassage portion 72 of safety valve 41.

The fusible connection means 71 comprises a tubular member 74 open atits upper end and connected at its lower end tothe wall ofpassageportion 72 by a screw eye 75. A rod 77 extends loosely into tubularmember 74 and is connected at its upper end to wire 70. An annular layerof fusible material 78 normally bonds the rod 77 to the interior oftubular member 74 and thus holds fuel valve 66in open position byexerting thereon a counterclockwise rotative force against theresistance of spring 67.

The valve mounting arrangement illustrated in FIG. 2 operates insubstantially the same manner as that of the previously describedembodiment illustrated in FIG. 1.

Cir

If valve 52 fails to open at a desired pressure for any reason,excessive temperature fuses the low melting alloy 50 and upward pressureagainst the valve assembly causes the mounting member 48 and the valvecarried thereby to move outwardly, that is upwardly as viewed in FIG. 2.This releases the pressure in the boiler and likewise relaxes thetension of wire 70 whereupon spring 67 closes the fuel valve.

If excessive pressure is reached in the boiler and the safety valve doesfunction in the expected manner by opening of valve element 52, theescaping steam through passage 72 rapidly raises the temperature of theannular alloy filling 78 of fusible connection 71 which releases rod'77from tubular member 74. Thus the fuel valve 66 is closed either bymelting of the fusible joint at '50 or by normal operation of the safetyvalve under excessive pressure.

Note that an opening 80 in passage portion 72 permits rod'77 and itsconnection with wire 70 to move freely upwardly upon melting of thematerial 78 to permit free closure of valve 66 under such circumstances.In this embodiment of the invention means are provided for giving a moreor less permanent indication that the safety valve has operated, eventhough the valve member 52 thereof subsequently closes. This indicationremains by reason of the separation of rod 77 from tubular member 74.

I claim:

1. In a safety valve arrangement for fluid heating vessels subject toelevated pressures and temperatures, a tubular'member adapted to befixed at one end to such vessel in fluid communication with the interiorof the vessel, a safety valve having a mounting stem portion includinga' pressure inlet passage to said safety valve and a valveelementopenable upon predetermined pressure in said inlet passage, saidmounting stem and said tubular member being in telescoping relation witha radial space therebetween, and a low temperature alloy in said radialspace and bonded to said stem and said tubular member to normallyconnect the same against relative axial movement, said alloy beingfusible at a predetermined temperature torelease said sleeve from saidtubular member to disconnect the safety valve from said vessel, meansfor controlling the supply of'heating energy to said vessel, meansbiasing said control means to a position for preventing such energysupply, and holding means'between said valve element and said controlmeans for holding said control means in energy supplying position whensaid valve is in normal seated position, said holding means beingresponsive to either movement of said valve element to an open positionor disconnection of the safety valve from said vessel to release saidcontrol means for movement to energy supply preventing position, wherebysaid control means moves to energy supply preventing position when saidvalve element moves toward open position or said fusible alloy releasessaid safety valve from said vessel.

2. In a safety valve arrangement for fluid heating vessels subject toelevated pressures and temperatures, a tubular member adapted to befixed at one end to such vessel with the interior of the tubular memberin fluid communication with the interior of the vessel, a safety valvehousing including a valve chamber and a pressure inlet sleeve openinginto said chamber, a valveelement normally closing communication betweensaid sleeve and said chamber, spring means for 'yieldably holding saidvalve in closed position, said pressure inlet sleeve telescoping withinsaid tubular member and spaced radially inwardly therefrom, and a lowtemperature alloy in said radial space and fused to said sleeve and saidtubular member to normally connect the same against relative axialmovement, said alloy being fusible at a predetermined temperature torelease said sleeve from said tubular member, means for controlling thesupply of heating fuel to said vessel, means biasing said control meansto a position for preventing such fuel supply, and tension holding meansbetween said valve element and said control means for holding saidcontrol means in fuel supplying position when said valve is in normalseated position, said holding means being responsive to either movementof said valve element to an open position or disconnection of the safetyvalve from said vessel to release said control means for movement toenergy supply preventing position, whereby said control means moves tofuel supply preventing position when said valve element moves towardopen position or said fusible alloy releases said safety valve from saidvessel.-

3. In a safety valve arrangement for fluid heating vessels subject toelevated pressures and temperatures, a tubular member adapted to befixed at one end to such vessel with the interior of the tubular memberin-fluid communication with the interior of the vessel, a safety valvehousing including a valve chamber and a pressure inlet sleeve openinginto said chamber, a valve element normally closing communicationbetween said sleeve and said chamber, spring means for yieldably holdingsaid valve in closed position, said pressure inlet sleeve and saidtubular member being in telescoping relation with an annular spacetherebetween, and a low temperature alloy in said radial space andbonded to said sleeve and said tubular member to normally connect thesame against relative axial movement, said alloy being fusible at apredetermined temperature to release said sleeve from said tubularmember, means for controlling the supply of heating energy to saidvessel, means biasing said control means to a position for preventingsuch energy supply, and holding means between said valve element andsaid control means for holding said control means in energy supplyingposition when said valve is in normal seated position, said holdingmeans being responsive to either movement of said valve element to anopen position or disconnection of the safety valve from said vessel torelease said control means for movement to energy supply preventingposition, whereby said control means moves to energy supply preventingposition when said valve element moves toward open position or saidfusible alloy releases said safety valve from said vessel.

4. In a safety valve construction for boilers and like vessels subjectto elevated pressures and temperatures, a tubular member adapted to befixed at one end to such vessel in fluid communication with the interiorof the vessel, a safety valve having a mounting stem portion including apressure inlet passage to said safety valve, said mounting stem and saidtubular member being in telescoping relation with an annular spacetherebetween, a low temperature alloy in said annular space and bondedto said stern and said tubular member to normally connect the sameagainst relative axial movement, said alloy being fusible at apredetermined temperature to release said stem from said tubular memberto disconnect the safety valve from said vessel, means for controllingthe supply of heating energy to said vessel, means biasing said controlmeans to off position, and holding means extending between said safetyvalve and said control means normally holding the latter in on position,said holding means being responsive to either movement of said valveelement to an open position or disconnection of the safety valve fromsaid vessel to release said control means for movement to energy supplypreventing position, said holding means including a fusible connectionlocated in the path of escaping steam when said safety valve is open,whereby said control means moves to off position either when said safetyvalve opens and said fusible connection melts or when the lowtemperature alloy in said annular space melts.

References Cited by the Examiner UNITED STATES PATENTS 1,142,902 6/1915McNutt 137-74 X 1,868,708 7/1932 Hunt 137-75 2,036,391 4/1936 Bradley13774 X 2,194,541 3/1940 Buttner l37--73 2,410,900 11/1946 Radbilll22--504.1

ISADCR WEIL, Primary Examiner.

R. GERARD, Assistant Examiner.

1. IN A SAFETY VALVE ARRANGEMENT FOR FLUID HEATING VESSELS SUBJECT TOELEVATED PRESSURES AND TEMPERATURES, A TUBULAR MEMBER ADAPTED TO BEFIXED AT ONE END TO SUCH VESSEL IN FLUID COMMUNICATION WITH THE INTERIOROF THE VESSEL, A SAFETY VALVE HAVING A MOUNTING STEM PORTION INCLUDING APRESSURE INLET PASSAGE TO SAID SAFETY VALVE AND A VALVE ELEMENT OPENABLEUPON PREDETERMINED PRESSURE IN SAID INLET PASSAGE, SAID MOUNTING STEMAND SAID TUBULAR MEMBER BEING IN TELESCOPING RELATION WITH A RADIALSPACE THEREBETWEEN, AND A LOW TEMPERATURE ALLOY IN SAID RADIAL SPACE ANDBONDED TO SAID STEM AND SAID TUBULAR MEMBER TO NORMALLY CONNECT THE SAMEAGAINST RELATIVE AXIAL MOVEMENT, SAID ALLOY BEING FUSIBLE AT APREDETERMINED TEMPERATURE TO RELEASE SAID SLEEVE FROM SAID TUBULARMEMBER TO DISCONNECT THE SAFETY VALVE FROM SAID VESSEL, MEANS FORCONTROLLING THE SUPPLY OF HEATING ENERGY TO SAID VESSEL, MEANS BIASINGSAID CONTROL MEANS TO A POSITION FOR PREVENTING SUCH ENERGY SUPPLY, ANDHOLDING MEANS BETWEEN SAID VALVE ELEMENT AND SAID CONTROL MEANS FORHOLDING SAID CONTROL MEANS IN ENERGY SUPPLYING POSITION WHEN SAID VALVEIS IN NORMAL SEATED POSITION, SAID HOLDING MEANS BEING RESPONSIVE TOEITHER MOVEMENT OF SAID VALVE ELEMENT TO AN OPEN POSITION ORDISCONNECTION OF THE SAFETY VALVE FROM SAID VESSEL TO RELEASE SAIDCONTROL MEANS FOR MOVEMENT TO ENERGY SUPPLY PREVENTING POSITION, WHEREBYSAID CONTROL MEANS MOVES TO ENERGY SUPPLY PREVENTING POSITION WHEN SAIDVALVE ELEMENT MOVES TOWARD OPEN POSITION OR SAID FUSIBLE ALLOY RELEASESSAID SAFETY VALVE FROM SAID VESSEL.